1. Technical Field
This invention relates to piston and cylinder stops that secure the piston rod when it is in extended position to prevent accidental deactivation of the piston and cylinder assembly when in extended support linkage load bearing engagement.
2. Description of Prior Art
Prior art devices of this type have been directed to a variety of cylinder locks that will engage the piston and cylinder and keeping it from retracting unintentionally. See for example U.S. Pat. Nos. 4,043,253, 4,122,758, 4,483,564 and 4,947,705.
In U.S. Pat. No. 4,043,253 a boom cylinder stop for lift cylinders is disclosed having a tubular bearing mounted on the rod so that when extended it will drop down and engage the cylinder holding same in place.
U.S. Pat. No. 4,122,758 is directed to a service support wherein a U shaped bracket is bolted to an extended lift rod, locking it in place.
U.S. Pat. No. 4,483,564 claims an oil well sucker rod safety block formed of a slotted pipe with a handle that is positioned over the well spring and held in place by end caps and engagement of the string thereon.
U.S. Pat. No. 4,947,705 discloses a method and apparatus for maintaining a load raising linkage in raised position. The device comprises a locking member pivoted between an unlocked position and a locking position over the extended piston rod.